The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Spark plugs for internal combustion engines typically include a ground strap that is spaced apart from a central electrode to form the spark plug gap. Controlled electrical arcing across the gap typically provides the ignition spark to ignite compressed air fuel mixture within the combustion chamber. The ground strap is typically connected to one side of the main body of the spark plug. The orientation of the ground strap relative to the intake and exhaust valves of the engine can change the performance (e.g., fuel economy) of the engine by altering the flow patterns of the air-fuel mixture and combustion gasses in the combustion chamber.
Consistently orienting the ground strap in a predetermined and desired rotational location relative to the valves can improve consistency between the performance of different engines during production. The orientation of the ground strap typically depends on the characteristics of the internal threads of the engine cylinder head and the external threads of the spark plug. However, it can be difficult to determine if the internal threads of the cylinder head and the external threads of each individual spark plug are formed to properly orient the spark plug. Typically, a spark plug or gauging plug must be threaded into the cylinder head and torqued to a predetermined value to determine if the threads of the cylinder head are properly oriented. However, such processes can be slow and can produce additional wear on the cylinder head. Repeated use of the spark plug or gauging plug can also wear down the spark plug or gauging plug and cause inaccurate readings.
The device and thread gauging method of the present disclosure overcome these limitations of the typical spark plug gauging process and can ensure a properly oriented spark plug in a first part while reducing wear on the cylinder head.